Incidence and clinical significance of ventricular arrhythmias in dilated cardiomyopathy

Abstract

The diagnosis of dilated (congestive) cardiomyopathy was made in 75 patients on the basis of clinical, ECG, echo and angiographic-haemodynamic findings. Ambulatory 24-hour monitoring was undertaken in all patients. Nearly all of them (93%) had ventricular extrasystoles (VES), 35% more often than 1000/24 h. In 15% VES occurred in pairs, in 44% as ventricular tachycardia. In general, frequent VES (greater than 30/h) also came in pairs and/or as ventricular tachycardia. On the other hand, not all patients with such complex arrhythmias also had frequent VES. In about 70% of all patients with ventricular tachycardia such episodes were registered repeatedly, in more than 40% more than five tachycardia episodes per 24 hours. In the majority of patients the tachycardia consisted of three (33%), four (12%) or five (18%) consecutive ventricular complexes. All episodes of ventricular tachycardia ended spontaneously and were clinically largely silent. Apparently there was no clinically relevant correlation between frequency and severity of the arrhythmia, on the one hand, and extent of abnormal ventricular function, on the other. These findings indicate that frequent and complex ventricular arrhythmias are a characteristic feature of dilated (congestive) cardiomyopathy. If they occur in heart disease of seemingly unknown aetiology, dilated cardiomyopathy should be suspected. Preliminary findings of long-term observation indicate that patients with frequent ventricular tachycardias have a higher risk of sudden death.